This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Assess the long term safety and efficacy of Myozyme treatment in patients with late onset Pompe disease who were previously treated under the placebo-controlled, double blind study AGLU02704. Orphan disease status.